Mack 13GC317 Exhaust Valve Seat PAI 2548-STD (Pack6)CROSS REFERENCE: 4103 5200545778 13GC317 5200545778 APPLICATION: Mack E7 Aset E tech Multiple Use Application. BRAND: PAI 2548 STD Mack 13GC317 Exhaust Valve Seat PAI 2548 STD. Truck repair parts and heavy truck parts. Supports valve alignment and helps regulate exhaust flow under heat conditions. All components are proudly manufactured in the U. S. A. by PAI Industries Inc., an ISO9001 certified company with over 50 years of experience in the heavy